KR101177983B1 - Chemical vapor deposition reactor - Google Patents

Abstract

A CVD reactor is provided, such as a MOCVD reactor that performs organometallic chemical vapor deposition of the epitaxial layer. The CVD or MOCVD reactor generally comprises a flow flange assembly, an adjustable proportional flow injector assembly, a chamber assembly and a multi-segment central rotating shaft. The reactor provides a novel structure for special components that function to improve the performance of the deposition while reducing the use of gases.

Description

Chemical Vapor Deposition Reactor {CHEMICAL VAPOR DEPOSITION REACTOR}

This application claims the benefit of US Provisional Patent Application No. 60 / 979,181, filed October 11, 2007, which is incorporated by reference in its entirety.

The present invention relates to a chemical vapor deposition (CVD) reactor comprising an organometallic chemical vapor deposition ("MOCVD") reactor.

Chemical vapor deposition ("CVD") reactors, in particular organometallic chemical vapor deposition ("MOCVD") reactors, are used to deposit solid material layers onto wafers. Such materials typically include compounds of group III and group V group elements of the periodic table (hereinafter referred to as materials III-V, but also include "II-VI materials"). Materials such as silicon (Si), silicon carbide (SiC), zinc oxide (ZnO) and other materials are also deposited on wafers or other surfaces using these reactors. Typically, such reactors are used in the manufacture of solid-state semiconductor microelectronics, optics, and photovoltaic (solar) devices, and in the manufacture of other electronic / optoelectronic materials and devices.

In operation, a typical flat-cylindrical wafer carrier with one or more wafers loaded in a shallow pocket on top of the wafer carrier is typically required by a heater assembly located below the bottom surface. 450-1400 ° C.).

The continuously-fed gas mixture is directed to flow over the surface of the wafer and the heated wafer carrier. Most of the gas mixture (about 75-95%) is a carrier gas, which is a unique inert gas that functions to define a general flow pattern in the reactor and to properly dilute the reactant gas. (Usually hydrogen or nitrogen). The remainder of the gas mixture consists of the reactive gas of the Group V group (about 4-23%), the reactive vapor of the Group III group (about 1-2%) and the dopant gas or vapor (a trace amount).

The gas of the group V group is decomposed immediately on and on the surface of the wafer and the heated wafer carrier, so that the central atoms of the group V group element are inserted into the material layer deposited on both the surface of the wafer and the wafer carrier. The gas of the group III group is similarly decomposed to provide atoms of the group III group element. The dopant gas is similarly decomposed to provide atoms that function to alter the electrical conductivity of the semiconductor material.

The gas mixture (including reaction byproducts) flows radially outward over the surfaces of the wafer and wafer carrier and then exits the reactor through one or more discharge ports. In particular, since most materials are optimally deposited at sub-atmospheric pressures, vacuum pumps are commonly used to draw gas mixtures through the reactor. After passing through the heated wafer carrier, the gas mixture begins to cool rapidly, causing rapid condensation of the by-products in the solid state. This tends to coat the inner surface of the reactor chamber under the discharge tube and wafer carrier.

The wafer carrier is typically from 100 to 1000 RPM or more to reduce the thickness of the mass-transport boundary layer, which evenly distributes the flow gas mixture and increases the efficiency of reactant usage and by-product removal. Is rotated.

Using this method, materials are deposited in a batch manner. It is not continuously fed during the batch run of reactants. Typical batch operation is performed as follows. Only the carrier gas is supplied at a low flow rate during the initial stage of operation. Then, simultaneously, the rotation of the wafer carrier is gradually increased to the required value, the temperature of the wafer carrier is increased to the required value, and the flow rate of the carrier gas is increased to the required value.

The Group V group reactant gas is first converted into the reactor at a certain temperature level to stabilize the surface of the substrate wafer (to prevent deposition of Group V group atoms), and then the Group III group and the dopant gas are removed from the material layer. Conversion to produce a "growth" (material growth occurs only when the sources of at least one Group V group and at least one Group III group are converted to the reactor). While temporary pauses may occur where no Group III group or dopant gas is supplied to the reactor, the gas of at least one Group V group is typically supplied during the entire growth phase (wherein the temperature is about 350- 400 ° C. or higher).

As all layers of material grow, the temperature gradually decreases. If the temperature is below about 350 ° C., the reaction gas of the group V group is switched off and the rotation, temperature and flow rate of the carrier gas are reduced to the starting level. The wafer is then removed from the wafer carrier by either opening the reactor chamber top or transferring the entire wafer carrier out of the reactor chamber by mechanical means. Depending on the material to be deposited, the same wafer carrier may be used for several batch operations or just one operation before the excess material deposited on the exposed top surface is cleaned.

There are a number of known MOCVD reactor systems currently available on the market. Each of these known MOCVD reactors suffers from defects and disadvantages.

The first known design utilizes a large cylindrical vessel with a gas flow injection top lead to evenly spread the flow over the entire lid area. To some extent, vertical separation prevents the by-products from depositing on the inner lead surface into which the gas flow enters. However, the design of the leads is to cause pre-reaction and byproduct deposition, due to inefficient isolation of diffusion “zones” of multiple gases in the leads; Inefficient diffusion of gas flow from the feed gas tube over a large area of area, leading to deposition of additional material on the inner lead surface as well as non-optimal material properties; And requiring a high flow rate of gas to produce a relatively uniform outlet flow from the lid through the volume of the large chamber.

The second design uses a short cylindrical vessel with a gas flow injection top lead closely spaced to the (heated) deposition surface. Close spacing is effective in minimizing reactor volume, allowing gas to effectively contact the deposition surface, and isolating the gas chamber. However, due to the close spacing, it causes deposition of by-products on the inner lid surface and requires cleaning after almost every process operation, requiring large maintenance time and cost, and low productivity, in addition to high maintenance costs, The cost is very high due to the complexity and large area of the leads.

Both designs are expensive to use. The first design has very high operating costs and produces low quality and performance products. The second design has a relatively low operating cost, but requires high system maintenance.

CVD reactor systems with low production costs and operating costs are desirable. Preference is given to CVD reactor systems having improved properties of deposition materials, high uptime and high quality.

The present invention provides a chemical vapor deposition (CVD) reactor comprising an organometallic chemical vapor deposition (MOCVD) reactor that performs organometallic chemical vapor deposition of epitaxial layers. The CVD or MOCVD reactor generally comprises one or more flow flange assemblies, an adjustable proportional flow injector assembly, a chamber assembly and a multi-segment central rotating shaft.

The CVD reactor of the present invention provides a new structure for a particular component that functions to improve deposition while reducing the use of gases. In one aspect of the invention, a number of CVD reactor components with new structures are described. In another aspect, new components are described that address the problems of conventional CDV reactors. For example, the chamber top and sidewalls have significantly different structures than conventional components. The top and sidewalls form a flared or curved concial surface. The outlet region of the reactor also has an improved structure that includes a tapered or sloped surface. In one embodiment of the present invention a new gas injector is included to further improve performance and economy.

The design of the present invention provides a number of advantages. The CVD reactor reduces the volume of the reactor, provides a flow-guide surface that directs incoming gas flows directly into the deposition surface, and back-entry the reactant gas used into the main reaction volume. It provides an additional flow-guide surface that provides high uniformity of fluid cooling or temperature control of the core internal reactor surface and provides a means to reduce heat loss from the deposition surface.

The design of the reactor addresses but is not limited to many of the problems of existing designs, including: (1) high and inefficient use of gases and chemicals, (2) non-uniform distribution of incoming gas streams, ( 3) expensive manufacturing costs of the equipment and (4) deposition of problematic byproducts on the internal reactor surface. The result of the reactor design has the advantages of low operating costs, improved properties of the deposited material layer and low mechanical maintenance needs.

The flow flange assembly comprises a tapered or flared cone top surface that is three-dimensionally tapered or flared, in contrast to vertical cylindrical walls of other designs, and a thin fluid gap immediately behind the surface. This design reduces reactor volume and gas usage, effectively directs gas to the deposition surface for more efficient chemical usage, and provides near uniform radial direction speeds for improved deposition uniformity.

The adjustable proportional flow injector has several features including an area smaller than the deposition surface, an isolated flow zone, a single adjustable flow zone without separate barriers, and a uniform cooling fluid flow profile. This feature addresses several problems with prior art injectors by providing low gas flow rates, low manufacturing costs, zone cross leaks and the absence of pre-reactions and by-product deposition, and improved uniformity of deposition materials. do.

In one embodiment of the invention, the adjustable proportional flow injector assembly includes a fluid cavity for adjusting gas temperature prior to injecting gas into the reactor chamber and one or more gas chambers for maintaining one or more reactant gas streams separately. ). The adjustable proportional flow injector assembly receives one or more gas inlet streams from the feed tube, diffuses / disperses this flow at a uniform outlet flow rate, and keeps the gas stream separated until it is discharged, while also adjusting the gas. If possible, adjust the temperature of the gas as it exits the proportional flow injector assembly.

In one embodiment of the invention, the chamber assembly comprises a generally conical or inclined lower flow guide. The lower flow guide prevents gas from recirculating back to the reaction zone, improves the smoothness of flow from the outer edge of the wafer carrier to the discharge port for a more stable overall reactor flow profile, and provides better temperature uniformity and improved Reduce heat loss at the outer edge of the wafer carrier for material properties.

The embodiment of the wafer carrier has a cylindrical plate made of a high temperature resistant material that holds the substrate wafer (s) in the reactor volume, and in one embodiment of the invention transfers the heat received from the heater assembly to the wafer.

The central rotating shaft generally communicates with the wafer carrier to generate a rotational movement of the wafer carrier. In one embodiment of the invention, the central rotating shaft is coupled with a rotary vacuum feedthrough, typically a ferrofluid seal type, through the baseplate central axis, supporting and rotating the wafer carrier in the reactor. .

In a particular embodiment of the invention, the reactor comprises a two part wafer carrier having a top and a bottom, the top having optimal properties for holding the substrate wafer and the bottom having optimal properties for heat absorption. .

In one embodiment of the invention a multi-segment central rotating shaft is provided. The multi-segment shaft has two or more segments that can optionally be used in the reactor. At least one segment of the multi-segment shaft is made of a material having low thermal conductivity. The multi-segment shaft has high heat transfer resistance and may have segment interfaces designed to reduce heat loss from the wafer carrier. The multi-segment shaft can generate additional heat near the center of the wafer carrier and provide a thermal barrier to heat loss from the wafer carrier and / or shaft.

According to the structure of the reactor according to the invention there is an effect that can improve the performance of the deposition while reducing the use of gas.

The following is a general description of the drawings described herein.
1 is a perspective view according to one embodiment of an entire reactor chamber assembly.
2 is a side view according to one embodiment of an entire reactor chamber assembly.
3-5 are cross-sectional views according to one embodiment of the entire reactor chamber assembly.
6 is a perspective view according to one embodiment of a flow flange assembly.
7 is an exploded side view according to one embodiment of a flow flange assembly.
8 is an exploded bottom view according to one embodiment of a flow flange assembly;
9A-9C are three side cross-sectional views according to one embodiment of an upper flow guide.
10 is a detailed cross-sectional view according to one embodiment of the upper flow guide.
11 is a side view according to one embodiment of an adjustable proportional flow injector assembly.
12 is an exploded side view according to one embodiment of an adjustable proportional flow injector assembly.
13-15 are three cross-sectional views according to one embodiment of an adjustable proportional flow injector assembly.
16 is a top interior view according to one embodiment of an adjustable proportional flow injector gas chamber machine.
17 is a bottom view according to one embodiment of an adjustable proportional flow injector assembly.
18 is a detailed cross-sectional view of the dual O-ring seal of the adjustable proportional flow injector assembly sealed to the flow flange assembly.
19 is a perspective view according to one embodiment of the chamber assembly.
20 is a top view of a chamber assembly according to one embodiment.
21A and 21B are two exploded views according to one embodiment of a central rotating shaft assembly.
22 is a side view according to one embodiment of a central rotating shaft assembly.
23 is a cross-sectional view according to one embodiment of a central rotating shaft assembly.
24 is a detailed cross-sectional view according to one embodiment of a central rotating shaft assembly.
25A-25C illustrate another embodiment of a subassembly of the gas chamber of the adjustable proportional flow injector assembly.

The present invention will be described in detail using preferred embodiments. However, the present invention is not limited by this embodiment. In addition, the requirements in the embodiments are freely applicable to other embodiments, and the requirements are interchangeable with each other unless special conditions are added.

In particular, the CVD reactor (chemical vapor deposition reactor) or the MOCVD reactor (organic metal chemical vapor deposition reactor) and the components and components of the reactor will be described later in detail. The CVD reactor or MOCVD reactor may include other components and components not specifically mentioned herein. It will also be appreciated that the scope of the present invention relates to a CVD reactor or a MOCVD reactor that may include some of the components and components described herein or may include all of the components and components described herein. .

1 is a front perspective view according to one embodiment of the entire reactor assembly 1. The entire reactor assembly 1 consists of three subassemblies which together form the entire reactor assembly 1. The three subassemblies are a flow flange assembly 3, an adjustable proportional flow injector assembly 5 and a chamber assembly 7.

FIG. 2 shows some of the individual components seen from the side of the reactor assembly 1 and from the outside of the reactor 1. These components are described in more detail below.

3 to 5 show cross sections of the entire reactor assembly 1 showing the interconnection of the three subassemblies and cross sections of the individual components that make up the three subassemblies. The flow flange assembly 3, the adjustable proportional flow injector assembly 5 and the chamber assembly 7 are shown in FIGS. 1 and 2. Each component of the three subassemblies 3, 5 and 7 is shown and will be described in more detail below.

6-10 and 18 show several views according to one embodiment of the flow flange assembly 3. The flow flange assembly 3 comprises a main flange body 30 and has an upper opening 31 at the top which forms a mating port for the flow injector assembly 5, the chamber at the bottom end. To the assembly 7 (shown optimally in the cross-sectional view of FIGS. 3-5). The flow flange assembly 3, together with the flow injector and wafer carrier, forms a gas flow profile within the reactor volume 33 and the reactor volume and has an upper flow guide 32 fitted to the main flange body 30.

The upper flow guide 32 preferably has a conical outer facing surface 34 that is gradually tapered in three dimensions as opposed to the vertical cylindrical wall of the prior art. The upper flow guide 32 is positioned within the main flange body 30, as best shown in FIGS. 7 and 8. The lower surface 35 of the main flange body 30 is formed between the upper flow guide 32 and the main flange body 30 so that a thin fluid gap or cavity 37 is formed immediately behind the upper flow guide 32. It has a corresponding shape to accommodate the inner facing surface 36 of the upper flow guide 32 (shown optimally in FIGS. 8-10). In one embodiment of the present invention, as shown in FIGS. 9A-9C, fluid cavity assembly channels 41, 42 (two points here) are connected to the thin fluid cavity 37 through the flow orifice 40. .

The structure of the upper flow guide 32 minimizes the reactor chamber volume, suppresses the recycle vortex in the reactor chamber volume 33, and provides efficient contact of the reactant gas with the wafer carrier surface 77.

In one embodiment of the invention, as best shown in FIGS. 3-5, the upper flow guide 32 is a first (upper) approximately equal to the diameter of an adjustable proportional flow injector (APFI) 5; It has a second (lower) diameter D2 approximately equal to the diameter D1 and the diameter d3 of the wafer carrier 76. As shown in the figure, the first diameter D1 is smaller than the second diameter D2. Preferably, the first diameter D1 is about 0.2 to 0.5 times the second diameter D2. The upper flow guide 32 is not exactly conical but rather curved like a guide extending downward and widening in a trumpet shape as it approaches the second diameter D2. The upper flow guide 32 produces a gas flow pattern in which a uniformly distributed downward-flow gas stream is directed towards the wafer carrier 76, which also rotates laterally to expand the reactor chamber volume. A small diameter flow injector 5 can be used to distribute the flow evenly over the large wafer carrier 76 without the occurrence of gas recirculation within 33.

The curved or flared profile of the upper flow guide 32 provides approximately equal radial gas velocities. The upper flow guide 32 with this structure is shown as an expansion cone upper flow guide 32. Without wishing to be bound by theory, in order to move the gas flow radially outward, the gas must traverse a continuously increasing cross-sectional area that increases with the radius of the cylindrical structure, with the result that the flow rate decreases. In order to maintain approximately constant velocity, the height H1 of the containing geometry is gradually reduced, so that the cross-sectional area (resulting in circumference times height) remains approximately constant, which neutralizes the increase in circumference along with the radius. .

The flow flange assembly 3 preferably has a fluid gap 37 located directly behind the upper flow guide 32 (between the upper flow guide 32 and the main flange body 30). In one embodiment of the present invention, the fluid gap 37 is relatively thin (about 0.1 inch or less), which is for fluids of about 1 gallon per minute and for fluids having a density and viscosity within about the size of water. Reynold's number values of less than 3200 can be generated indicating laminar flow in the gap and efficient use of fluids. This configuration reduces fluid usage and / or reduces the capacity of the fluid recycler when a reservoir / recycler heat exchanger system is used.

The flow flange assembly 3 may further comprise a flow from bottom / outside to top / inside through the fluid gap 37 for the removal of air and reverse-flow heat exchange. That is, the fluid flows back through the fluid gap from the direction in which gas flows in the reactor volume. This type of flow path through the fluid gap is in one embodiment from the supply channel 41 optionally below through one or more feed pipes (not shown). Each feed channel 41 has one or more flow suppressing orifices 40 close to the ends of each feed channel 41. The flow inhibiting orifice 40 sufficiently suppresses the flow to create a uniform flow transfer around the periphery of the fluid gap 37 through each feed channel just before the same flow rate of fluid enters the fluid gap 37. The fluid flows radially inwardly through the fluid gap 37 and then passes through a second set of flow inhibiting orifices 40 that selectively moves the fluid through the one or more return tubes (not shown) to the return channel 42. do. Fluid is supplied through feed channel inlet tube 45 and returned through fluid outlet tube 46. The flow characteristics of the fluid in the fluid gap 37 improves the uniformity of temperature in the reactor chamber volume 33, which improves the uniformity of the gas flow profile and the deposition uniformity. The flow pattern from bottom / outside to top / inside in the fluid gap 37 causes effective removal of air from the gap 37 and reverse-flow heat exchange.

At the outermost diameter D2 of the upper flow guide (ie, at the end of the upper flow guide close to the wafer carrier 76), the gap 43 between the upper flow guides 32 and the outermost diameter of the wafer carrier 76. The wafer carrier upper surface 77 at (d3) generally inhibits or prevents the recirculation of the gas blown over the wafer carrier 76. In particular, as shown in FIGS. 3-5, the wafer carrier 76 is on top of the central rotating shaft 75. The outermost diameter D2 of the upper flow guide 32 is approximately equal to the outermost diameter d3 of the wafer carrier when the upper flow guide 32 is closest to the wafer carrier 76. In this respect, the separation between the two parts H2 is at a minimum, and the gap 43 facilitates to inhibit or prevent the recirculation of the blowing gas in the reactor chamber volume 33. For example, the gap can have a dimension H2 of about 1.00 inches or less, for example about 0.25 inches or less.

The gas flowing downward from the adjustable proportional flow injector assembly 5 flows radially outwards in the reactor chamber volume 33 laterally. When the gas reaches the gap 43, the gas can achieve a maximum flow rate, and after the gap 43 the gas begins to expand and decelerate in the discharge collection zone 44 close to the gap 43. This prevents retrograde recycling of already used gas mixtures (ie, gas moved from the wafer carrier 76 and the reaction zone thereon).

In a preferred embodiment of the invention, the reactor 1 with the expansion conical upper flow guide 32 also includes a lower flow guide 72 (described in detail below). The lower flow guide 72 prevents gas recirculation back to the reaction zone, improves the smoothness of flow from the outer edge of the wafer carrier to the discharge port for a more stable overall reactor flow profile, provides better temperature uniformity and Reduce heat loss at the outer edge of wafer carrier 76 for improved material properties.

An adjustable proportional flow injector assembly 5 according to one embodiment of the invention is shown in FIGS. 11-18 and 25. The adjustable proportional flow injector is a flow injector that receives a plurality of gas inlet streams from the feed tube and diffuses or disperses this flow for a uniform outlet flow rate and keeps the gas flow separate until discharged. Optionally, APFI 5 adjusts the temperature of the gas as it flows into the adjustable proportional flow injector. The APFI 5 is typically cylindrical in shape (perpendicular to the circular region) and fits within the flow flange assembly 3. Although a cylindrical APFI is shown in the figure, the APFI can be of any shape and the exact shape will generally be described by the shape (area) of the upper opening 31 to which it is coupled. For example, if the upper opening 31 is square or rectangular, then the APFI will have a corresponding square or rectangular shape to match it.

The adjustable proportional flow injector assembly 5 generally includes a support flange 51 and a gas chamber inlet tube through the support flange 51, which provide structural integrity for the components coupled to the support flange 51. Port 54. The support flange 51 further provides coupling of the entire adjustable proportional flow injector assembly 5 to the main flange body 30.

The APFI 5 includes one or more gas chambers 52. In one embodiment of the present invention, one or more gas chambers 50 may be processed with a gas chamber machine 52 and may comprise a plurality of gas chamber top walls or surfaces 57 and gas chamber bottom walls or surfaces 58. Can be formed. The gas chamber top wall 57 may be machined to form different zones, as shown in the plan views of FIGS. 16 and 17. The gas chamber 50 is separated from the other gas chambers 50 by the gas chamber vertical wall 59 extending from the gas chamber top wall 57 to the gas chamber bottom wall 58 to form the gas chamber 50. do. One or more gas inlets 54, which may be integrated in the gas chamber top wall 57, are in one or more gas chambers 50 of the adjustable proportional flow injector 5, for example in a vertical direction (ie gas chamber top). Gas is delivered in a direction substantially perpendicular to the wall 57 and the gas chamber bottom wall 58).

Each gas chamber 50 can receive a different gas stream, one or more gas chambers diffuse or disperse the gas, keep the first gas stream from another gas stream or keep each gas stream separate from the other, It is possible to create a uniform flow rate above a particular outlet surface area. In addition, each gas chamber 50 may be configured in the same or different shape as the other gas chamber 50.

For example, as shown in FIG. 16 (the support flange 51 is removed from the drawing), the outer gas chamber 50a, four intermediate gas chambers 50b, 50c and the inner gas chamber 50d are have. In one embodiment of the present invention, the gas chamber 50b contains a group III reactant, and the intermediate gas chamber 50c contains a group V reactant. The chambers 50a-50d are separated by a vertical wall 59, a gas chamber top wall 57 (not shown) and a gas chamber bottom wall 58.

The APFI 5 may also include a fluid cavity 60 located below one or more gas chambers 50. The fluid cavity 60 may be formed by coupling the fluid cavity machine 53 to the gas chamber machine 52.

FIG. 17 shows a bottom view according to one embodiment of the adjustable proportional flow injector assembly 5, showing the bottom surface of the fluid cavity machine 53. The gas chamber outlet 61 may extend or penetrate from the bottom wall 58 of the gas chamber through the fluid cavity 60, for example through the conduit tube 63, to the reactor chamber volume 33. The conduit tube 63 may have the same or different outer diameter and the same or different inner diameter. Penetrating the conduit tube 63 through the fluid cavity 60 allows the gas temperature to be adjusted before introducing gas into the reactor chamber volume 33 by appropriate control of the fluid temperature flowing through the fluid cavity 60. have. The fluid cavity 60 has a fluid cavity outlet 66 located approximately in the center of the fluid cavity 60 that is connected to the fluid cavity outlet tube 67. In addition, a fluid cavity inlet 68 is provided through a fluid cavity inlet tube 69 facing the outer circumference of the fluid cavity 60.

In one embodiment of the invention that includes a fluid cavity diffuser 65 (described in more detail below), the fluid cavity outlet 68 is located inside the circumference of the diffuser 65 and the fluid cavity inlet 68 is a diffuser. It is located outside the circumference of 65.

The adjustable proportional flow injector assembly 5 may optionally have one or more of the following features. In one embodiment of the present invention, the gas outlet hole 61 is preferably smaller in size than the gas inlet 54 (eg, may be about 100 to 10,000 gas outlet holes). The number of gas outlet holes 61 and the inner diameter and length of the conduit tube 63 extending through the fluid cavity 60 depend on the specific gas composition, flow rate, temperature and pressure, and also the bottom wall of the gas chamber ( Limited by the total surface area and manufacturability and cost of 58) and increases in failure and cost as the outer and inner diameters of the conduit tube 63 decrease and the spacing of adjacent gas outlet holes 61 decreases.

In general, however, the total cross sectional area of all conduit tubes 63 is preferably between two and six times greater than the cross sectional area of the gas inlet 54 for a given gas chamber. This arrangement takes into account the pressure drop across the set of conduit tubes of a given gas chamber, taking into account the large wall surface area and the corresponding fluid shear force and pressure drop of the small-diameter conduit tube 63 relative to the gas inlet 54. That is, it is preferable that the pressure drop from the gas chamber to the reactor chamber volume 33 is several torr to several torr.

Preferably, the gas chamber top wall 57 and the gas chamber bottom wall are approximately parallel. The top walls / surfaces 57 of all gas chambers may be in approximately the same plane or may be in different planes from each other. Likewise, the gas chamber bottom walls 58 of all gas chambers 50 may be in the same plane or in different planes.

The adjustable proportional flow injector assembly 5 may optionally include one or more intermediate dispersion baffle plates 55 approximately parallel to them between the gas chamber top wall 57 and the gas chamber bottom wall 58. Can be. When the intermediate dispersion baffle plate 55 is used, an upper gas chamber section 50a and a lower gas chamber section 50b are formed in the gas chamber 50 including the intermediate dispersion baffle plate 55. For example, the upper gas chamber section 50a may be formed by the gas chamber upper wall 57, the upper surface of the intermediate dispersion baffle plate 55 and any sidewall (s) 59 and the lower gas chamber Section 50b may be formed by gas chamber bottom wall 58, bottom surface of intermediate dispersion baffle plate 55, and optional sidewall (s) 59.

A gas outlet hole 61 in each gas chamber 50 passes through an outlet conduit (preferably a small diameter tube) through the fluid cavity 60 that can be attached or otherwise coupled to the fluid cavity machine 53. Coupled to 63 to form a bottom fluid cavity wall close to the bottom, which is the boundary surface of the reactor chamber volume 33. The outlet conduit 63 preferably has a hole pattern that matches the combined set of gas chamber outlet holes 61.

Another embodiment of the adjustable proportional flow injector assembly 5 relates to a fluid temperature control zone having a uniform and radial flow profile. A thermostatic fluid, for example a cooling fluid, enters the outer distribution channel 62. In one embodiment of the invention, the fluid cavity 60 has a fluid cavity diffuser 65. The fluid cavity diffuser 65 is preferably a thin cylindrical sheet metal ring having a height slightly greater than the height of the fluid cavity 60, and preferably as thin as possible. In a preferred embodiment of the invention, the cylindrical sheet metal ring is inserted into opposing circular grooves at the bottom surface of the gas chamber machine 53 and the top surface of the fluid cavity machine 52 and the depth of these two grooves. The sum of is preferably equal to the additional height of the flow dispersion barrier above the fluid cavity height such that the fluid delivered to the fluid cavities 60 at the plurality of inlets 68 at the outermost periphery of the fluid cavity is flow dispersing. The barrier 65 must move tangentially directly before flowing through a plurality of small holes 64, preferably spaced at equal intervals, and consequently the fluid cavity (from the outermost periphery of the fluid cavity 60). A uniform flow distribution in the radially inward direction from the central outlet 66 of 60 to the single outlet 66 is generated. The small hole 64 acts as a flow inhibiting orifice that sufficiently inhibits the flow to be the same flow through each hole 64.

25A-25C illustrate another method of manufacturing APFI. Not all APFI components described previously are shown. In order to easily and efficiently increase the manufacture and testing of APFI, the components of APFI can be assembled into replaceable modules or subassemblies. For example, the gas outlet hole sub-assembly 150 may be comprised of an upper plate 151, a lower plate 152, and a plurality of conduits 63. The upper plate 151 constitutes the bottom wall 58 of the gas chamber 50 described above. The lower plate 152 constitutes part of the bottom wall 58 of the fluid cavity machine 53 described above.

In this embodiment, the gas chamber machine 52 is configured to receive a plurality of gas outlet bore sub-assemblies 150 such that the top surface 153 of the top plate 151 of the gas chamber wall 59 described above. Engage on the same plane as one or more bottom surfaces 155. The seam between the top plate 151 of the adjacent gas outlet hole sub-assembly 150 descends along the centerline of the given bottom surface 155 of the gas chamber wall 59, thereby forming the fluid cavity 63 and the formed fluid cavity 63. Seals may be formed to prevent leakage between the gas chambers 50.

In the embodiment shown in FIGS. 25A-25C, between the bottom plate 152 of the adjacent gas outlet hole sub-assembly 150 and the bottom plate 152 of the given gas outlet hole sub-assembly 150 and the gas chamber machine. The seam of the lower fluid cavity wall 157 integrated with 52 may be sealed to prevent leakage between the fluid cavity 63 and the reactor chamber volume 33. In one embodiment of the invention, the lower surface 154 of each gas outlet hole sub-assembly 150 and the lower surface 154 of all other gas outlet hole sub-assemblies 150 and the gas chamber machine, although not required. Can be sealed in such a way as to be on the same plane as the bottom surface 156 of the substrate. Thus, fluid is delivered to the fluid cavity 63 through the plurality of fluid cavity inlets 68 and out through one or more fluid cavity outlets 66, and the fluid cavity diffuser 65 (not shown) is described above. It is positioned in a similar way.

Another embodiment of the invention is directed to a method of generating a pattern of gas outlets spaced approximately equally spaced in one or more radial patterns. According to this method, one or more circular hole patterns are arranged such that the holes are at the same distance from each other, for example square or hexagonal patterns. In the case of a radial zone that includes an adjustable proportional flow injector gas chamber, it may include a method of distributing the holes such that the holes are at approximately the same distance and area boundaries.

This method generally comprises (1) placing a first set of holes in a first line adjacent to and parallel to the first radial area boundary such that they have the same space in the radial direction between the holes, (2) the central axis of the machine An angle with a vertex in the central axis of the machine between a first point on the first line of the first radial distance from and a corresponding second point on the second line adjacent and parallel to the second radial area boundary (3) between the first hole at a given radius lying adjacent to the first radial area boundary and the corresponding second hole at the same radius lying adjacent the corresponding second radial area boundary. Determining the length of an arc having an origin at the center of the gas chamber machine, (4) dividing the length of the arc by the distance distance of the center-to-center hole required, and ( 5) Number of results as approximate integer Finishing. Steps (2) to (5) are repeated for each hole including the set described in step (1). This method produces a hole pattern with the same separation between the radial sets of holes and nearly the same separation of holes within each radial set of holes. In particular, this method is useful for creating a set of holes of approximately equal distance in a circular or semi-circular pattern over a small area, with irregularities in the hole spacing being more important than for patterns on large areas.

As also shown in FIG. 17, the reactor may include a gas distribution zone with tunability without zone separation barriers. In this embodiment, the reactor includes two or more gas inlet tubes 54 and a plurality of outlet holes 61 that function structurally to produce an adjustable outlet flow pattern. Without wishing to be bound by theory, by increasing or decreasing the amount flowing into one or more inlet tubes 54, an outlet flow hole, which does not have any optional vertical dividing wall 59 between any inlet tubes 54, is formed. Stagnation areas that would normally be created by areas below the dividing wall that could not have are removed.

The adjustable proportional flow injector assembly 5 may further comprise one or more sealing chamber tops, such as one or more O-ring sealing chamber tops, for cleaning and / or for changing baffles. In a preferred embodiment of the present invention, the gas chamber machine 52 includes an O-ring groove that is machined to the top surface of the vertical wall 59 separating the gas chamber, which removes the gas chamber zone top wall 57. . This is because an O-ring lying along the top surface of the vertical wall can seal directly to the other single intermediate sealing surface rather than to the bottom surface of the support flange 51 or the plurality of welding surfaces. By this configuration, the gas chamber can be opened and cleaned or inspected, and the number of necessary parts can be reduced.

In another embodiment of the invention, the adjustable proportional flow injector assembly 7 comprises a double O-ring seal with a vacuum barrier zone, as best shown in FIG. 18. Double o-ring seals are produced by the o-rings 91 of the o-ring grooves 92 in the gas chamber machine 52 and the fluid cavity machine 53. One o-ring 91a is located between the gas chamber machine 52 and the main flange body 30. The second o-ring 91b is located between the fluid cavity machine 53 and the main flange body 30. A vacuum cavity 93 is created between the APFI, main flange body 31 and O-ring 91. Differential sealing vacuum port tube 94 is included in main flange body 31 to create and release a vacuum seal. This configuration eliminates the adjustable proportional flow injector 5 while rejecting gas molecular permeation of the O-ring elastomer due to the significantly lower degree of vacuum created in the volume between the two O-ring seals than on either side of each seal. To facilitate.

An embodiment of the chamber assembly 7 is shown in FIGS. 19-20 and 3-5. The chamber assembly 7 has a reactor baseplate main body 70. The reactor baseplate main body is connected to the reactor cut top flange 100 through a reactor jar wall 101. The reactor cut top flange 100 engages with the main flange body 30 of the flow flange assembly 3. The base plate main body 70 includes a central rotating shaft 75 (described in more detail below), a baseplate discharge tube 79; (Can be mixed and is not currently included in designs and other drawings, but is left as some may be used in later designs); High current feedthrough 90; And ports for a number of components useful in CVD reactors, such as rotary vacuum feedthrough housing 88.

The chamber assembly 7 has components commonly seen in a CVD reactor such as a heater assembly that includes a heat reflecting shield and a heat source for heating the wafer carrier 76. In this embodiment, one or more heating elements 83 are located below the wafer carrier 76 and one or more heat shields 84 are located below the heating elements 83. For example, the heat source may be a filament for radiant heat or a copper tube for induction heat, and is preferably disposed in a concentric circular pattern to fit the circular area of the wafer carrier. Other types of heater assemblies may be used to heat the wafer carrier 76.

The chamber assembly 7 has a lower flow guide 72. The lower flow guide 72 has a frustoconical shape. The conical lower flow guide 74 has an inner diameter d1 and an outer diameter d2. Preferably, the inner diameter d1 is slightly larger than the outer diameter d3 of the wafer carrier 76, and the inner diameter d1 may be approximately equal to, smaller, or larger than the outer diameter d3 of the wafer carrier 76. . The lower flow guide 72 is substantially aligned with the upper surface 77 of the wafer carrier 76. The outer diameter d2 of the lower flow guide 72 is larger than the inner diameter d1 that creates the inclined surface in the downward direction.

In a preferred embodiment of the present invention, the inner diameter d1 is slightly larger than the outer diameter d3 of the wafer carrier 76. The space between the inner diameter d1 of the lower flow guide 72 and the outer diameter of the wafer carrier 76 allows the wafer to gradually expand, suppress or prevent the recirculation of the ejected gas below the outer edge of the wafer carrier 76. The gas is ejected from the gap 43 between the carrier 76 and the upper flow guide 32. The inner diameter d1 of the lower flow guide and the outer diameter of the wafer carrier 76 are very close to provide a narrow lower flow guide gap between the two, and as the lower flow guide gap becomes narrower, sufficient ejection of gas occurs and the reactor chamber volume Further suppression and prevention of gas recirculation within (33). In a preferred embodiment, the lower flow guide 72 is made of graphite.

The chamber assembly 7 comprises a lower flow guide reflector 74. The lower flow guide reflector 74 is located in the lower flow guide 72 and extends from the circumference of the wafer carrier 76 and slopes downward. The reflector 74 is composed of a thin piece of metal, preferably molybdenum. The reflector 74 serves to reflect heat inwardly and keeps heat constant on the surface of the lower flow guide 72.

In one embodiment of the invention, the lower flow guide 72 consists of one or more sections or pieces, such as a two-piece lower flow guide 72. Due to the close spacing between the lower flow guide 72 and the wafer carrier 76 and the high temperatures at which the wafer carrier 76 reaches during processing, the lower flow guide 72 in other embodiments is characterized by excellent temperature resistance and A first portion immediately adjacent to the wafer carrier 76 made of a material having a coefficient of thermal expansion substantially the same as or similar to that of the wafer carrier 76 (typically graphite, sapphire, or a heat resistant metal) and the material forming the first portion It has a second portion made of a material that is less expensive and does not have such a temperature resistance or coefficient of thermal expansion, such as a more easily formed material. In a preferred embodiment, the first portion is made of graphite to provide a coefficient of thermal expansion consistent with the appropriate temperature resistance and wafer carrier material.

The lower flow guide 72 is an extension of the wafer carrier extending from the diameter d3 of the surface of the wafer carrier 76 holding the wafer, in part or in whole, ie outside the wafer carrier surface 77 holding the wafer. It may be an edge profile. In this embodiment, some or all of the lower flow guide 76 is preferably a wafer carrier at some point along the circumference, or from the outer circumference of the wafer carrier upper surface 77 or lower surface 78. Is an extension of. In a particular embodiment, the lower flow guide 72 is a first section that is an extension of the wafer carrier 76 within the first few centimeters from the narrow gap 40 between the wafer carrier outer diameter 76 and the upper flow guide 72. And a second portion that is completely separated from the wafer carrier 76 and formed as a separation portion adjacent to the first portion.

The reactor wafer carrier 76 may have a conventional integral structure, but embodiments having other structures are also within the scope of the present invention. For example, in an embodiment of the present invention, the reactor may include a two-part wafer carrier 76 consisting of a removable top (ie, a platter or surface holding the wafer) and a bottom. The removable top can be made of a plurality of materials, preferably sapphire, the bottom can be made of graphite and heated for conducting heat of the bottom of the bottom and conducting heat of any wafer at the surface of the removable top and the removable top. It may further include a heating means, such as RF. The wafer carrier of the two parts may have a removable top that is replaced when necessary while the bottom can be reused.

For example, in one embodiment of the invention, the two part wafer carrier may have a sapphire removable top for holding the wafer and a graphite bottom supporting the sapphire removable top. The sapphire top is non-porous and does not decompose, resulting in a commonly used surface such as SiC encapsulant. The sapphire removable top may be cleaned more thoroughly, such as a quick wet chemical etch that is not readily performed on the graphite wafer carrier. The graphite bottom portion is a heat absorber for transferring conductive heat to the wafer on the removable top and the removable top surface, such as in a wafer pocket that can be processed at the top surface of the removable top.

In another embodiment of the present invention, the wafer carrier 76 is integral with a portion of the central rotating shaft 75, which is a shaft 75 extending downward from the center of the bottom surface 78 of the wafer carrier 76. In other words, it is directly machined to some. The central shaft 75 (or central rotary shaft 75) extends downwardly through the heating coil and consists of a suitable material for heating, for example a suitable material for induction heat. This central rotating shaft 75 can be heated as it is to the main portion of the wafer carrier 76 and provides a thermal barrier to the conductive heat losses that can occur with conventional support spindle shafts.

The central rotation shaft 75 for the wafer carrier 76 may typically be an integral structure, but embodiments with other structures may be used. For example, in the embodiment as shown in FIGS. 21-24, a multi-segment shaft 75 for rotating the wafer carrier is used, i.e. a shaft comprising one or more segments of the same material or different materials. . In a multi-segment embodiment, at least one segment will have approximately lower thermal conductivity than the remaining shaft segment (s) used. The multi-segment spindle is particularly useful in connection with radiant heaters but the invention need not be limited in this respect.

In the embodiment shown in FIGS. 21-24 there are three segments. The shaft upper segment 81 is in direct contact with the wafer carrier 76. The shaft upper segment 81 has a susceptor or flange 82 at the closest end with the bottom surface 78 of the wafer carrier 76. If a radiant heater is used, the upper segment is preferably made of a material such as aluminum or sapphire that has a lower thermal conductivity than the remaining segment (s) of one or more of the multi-segment shafts 75. The choice of such materials produces as high heat transfer resistance as possible. The segment interface between the multi-segment central shaft 75 and the wafer carrier 76 may be designed with a minimum surface to further improve heat transfer resistance. This feature improves temperature uniformity near the wafer carrier center region and reduces energy loss in the operation of the reactor.

In addition, when an induction heater is used in the reactor, the segment in contact with the wafer carrier (shaft upper segment 81) extends downward through the induction heating coil. In this case, the upper segment 81 is made of a material suitable for induction heating. For example, when an induction heater is used in the reactor, the upper segment 81 of the multi-segment central shaft 75 is preferably composed of graphite.

In one embodiment of the invention, the multi-segment shaft 75 has a shaft lower segment 85 made of a material that does not easily induce heat, such as sapphire. The shaft upper segment 81 and the shaft lower segment 85 are connected via a spacer 86 which is preferably made of alumina. The interface between the three (or more) segments preferably has a minimum surface contact area to produce as high heat transfer resistance as possible. The surface area can be reduced by including recesses 87 machined in the segment at the interface point shown in FIG. 24 to create a thin rail 96 around the circumference of the segment end. Contact between the segments occurs only in the thin rail 96 as opposed to the entire area of the segment ends. The segment is preferably secured by a vented head cap screw 97.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes may be made without departing from the spirit of the present invention. Thus, while the invention is described in the context of preferred embodiments, the full scope of the invention may be considered with reference to the scope of the following claims.

Claims (27)

A flow flange assembly comprising a main flange body and an extension conical upper flow guide connected to the main flange body, wherein a first fluid gap is formed between the extension conical upper flow guide and the main flange body;
A flow injector connected to the top of the flow flange assembly; And
A wafer carrier connected to the bottom of the flow flange assembly,
A second gap is formed between the expansion cone upper flow guide and the wafer carrier, and the expansion cone upper flow guide has a shape that widens in a trumpet shape as it extends downward toward the wafer carrier.
Wherein the expanding conical top flow guide, flow injector and wafer carrier form a reactor chamber volume and the second gap is minimized to inhibit recycling of the gas ejected within the reactor chamber volume during operation of the chemical vapor deposition reactor. Chemical vapor deposition reactor. The chemical vapor deposition reactor of claim 1, wherein the thickness of the first fluid gap is 0.1 inches or less. 3. The method of claim 2, further comprising: a first channel in fluid communication with the first fluid gap at the bottom or outside of the first fluid gap and a second channel in fluid communication with the first fluid gap at or above the first fluid gap. And wherein the fluid flows from one of the first channel and the second channel to the other channel to efficiently control the temperature of the outer surface of the expanded conical upper flow guide. 4. The chemical vapor deposition reactor as recited in claim 3, wherein the fluid flows back through the first fluid gap from the direction in which gas flows from the flow injector to the wafer carrier in the reactor volume. The flow guide of claim 1 wherein the expanding conical upper flow guide has an upper diameter equal to the diameter of the flow injector and a lower diameter equal to the diameter of the wafer carrier, wherein the upper diameter is smaller than the lower diameter and the minimum value of the second gap is 1.00 inches. Chemical vapor deposition reactor, characterized in that the following. The flow injector of claim 1, wherein the flow injector is connected to a coupling port in the flow flange assembly, the at least one supply tube, at least one gas chamber to receive the gas stream from the supply tube, a fluid cavity below the gas chamber and an outlet in the gas chamber. And at least one outlet conduit through the fluid cavity. The chemical vapor deposition of claim 1, wherein the flow injector has means for maintaining one or more gas streams that are separated before they are discharged, and the assembly has means for adjusting the temperature of the gas as the gas exits the assembly. Reactor. The chemical vapor deposition reactor of claim 1, further comprising a chamber assembly coupled to the flow flange assembly, wherein the chamber assembly comprises a conical shaped bottom flow guide. delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete

Images